Clutch device



Oct. 11, 1932. LEVEDAHL 1,881,728

CLUTCH DEVICE 3 Sheets-$heet 1 Original Filed Oct. 6. 1927 I a l 1 6%1/3 g7 A J-- 5% M v l 3nvcutqr, AxeZLez/eM,

N -mwm V Ctttorncg Get. 11, 1932. LEVEDAHL 1,881,728

CLUTCH DEVIG E Original Filed Oct.' 6, 1927 3 Sheets-Sheet I5 W I II 55AxeZLevedafiZ, inventor,

By a; Alia/an Patented Oct. 11, 1932 PATENT OFFICE AXEL LEVEDAHL, OFAURORA, ILLINOIS, ASSIGNOB TO INDEPENDENT PNEUMATIC TOOL COMPANY, OFCHICAGO, ILLINOIS, A CORPORATION OF DELAWARE cnurcn Davies Originalapplication filed October 6, 1927, Serial No. 224,372. Divided and thisapplication filed-October 28,

1929. Serial No. 402,913.

My invention relates to improvements in clutches generally, althoughmore specifically to a clutch mechanism which is particularly adaptedfor use in portable power driven tools, such as are employed forrotating screws or nuts. v

.This application is a division of my copending application, Serial No.224,372, filed Oct. 6, 1927, now issued as Patent No. 1,744,- 976,granted January 28, 1930, for improve-v ments in screw or nut drivingdevices for power operated tools.

This application covers the clutch assembly and its various parts orelements aloiie as well as in combination with each other, withoutreference to the clutch broadly in its combination in the tool asclaimed in the parent application (the patent aforesaid).

One object of my invention with respect to the clutch mechanism is toprovide a clutch device, including a pair offaxially aligned clutchmembers provided with a multiplicity of interchangeable clutch teeth ontheir opposed faces, and with the clutch members so constructed thattheir teeth engage in a single rotative position only of the clutchmembers, and which members are operable upon the development ofyapredetermined torsional stress between them to automatically separatethe to the other.

members and hold their teeth out of positive driving engagement forsubstantially a full revolution of one. clutch memberwith respectAnother object of my invention with respect to this clutch mechanism isto provide the clutch members with co-acting means for I the automaticseparation. of the clutch mem- V bers and to hold them out of positivedriving engagement for substantially a full revolution of one memberwith respect to the'other.

A further object of the invention with re-' spect to said clutchmechanism'is to provide the co-acting means on the respective clutchmembers in the form of interfitting grooves and projections adapted,when the projections are in the grooves, to permit the teeth of theclutch members to engage, and when the projections ride out of. thegrooves to sep arate said teeth to release the clutch members.

A further object of the invention is to arrange the grooves andprojections in two concentric tracks of diflerent radii with each Itrack preferably having but one groove or one ,through the clutchassembly, which drive is released when the two clutch members areautomatically disconnected through the operation of the releasing meansassociated with such clutch members.

The invention consists further in the matters hereinafter described andclaimed.

In the accompanying drawings-'- Fig. 1 shows a portable power driventool equipped with the device of m invention;

Fig. 2 has the guard or eeve for the so as to completely separateclutches in vertical section to show the clutches; I

Fig. 3 is an enlarged vertical sectional view through the device andassociated parts of the tool;

Fig. 4. is a view similar to Fig. 2 and shows themain clutchclosed andthe supplemental clutch held open by the means of my invention;

Figs. 5 and 6 are face views of the members of the supplementalclutch'to show the clutch separating means of my invention;

Figs. 7 and 8 are sectional views taken through these clutch members onlines 7-7 and 8'8, respectively, of Figs. 5 and 6; and

Fig. 9 is a diagrammatic view showing the action of one of the device.

In the drawings, I have shown a clutch embodying my invention applied toa portable electric drill, whiclrhas connected motor and gear cases 1and 2, with a tubular extension 3 on the forward end of the gear caseprojections of my and in which extension is journaled the rotary spindle4 of the tool with a bearing bushing 5 about the spindle in theextension, as shown in Figs. 2 and 3. The spindle 4 "is driven from thearmature shaft 6 of the motor of the tool through a speed reducinggearing which is located in the case 2 and comprises a gear 7 fixed onthe upper end of the spindle 4 and meshing with a pinion 8 carried by agear 9. The latter meshes with a pinion 10 carried by a gear 11 whichmeshes with gear teeth on the armature shaft 6 where it extends into thecase 2.

A shaft 12 has its inner end extending into and slidably-and rotatablysupported in the spindle 4, the latter being made hollow for thepurpose. The outer end of the spindle 4 extends beyond the extension 3and there is provided with an annular clutch member 13,

which has on its outer face a plurality of jaws or clutch teeth 14having inclined side faces 15, as shown in Figs. 2 and4. The clutchmember 13 is screwedor keyed on the outer end of the spindle 4 and turnswith the spindle when the latter is rotated by the armature shaft 6 ofthe motor during the operation of the tool.

A similar clutch member 16 is located on the shaft 12 just beyond theclutch member 13 and has on its inner face a plurality of ]B.WS orclutch teeth 17 made and arranged similar to the clutch teeth 14 andadapted to engage the same on pressing the tool against the work. (SeeFig. 4.) The clutch member 16, is rotatably connected with the shaft 12by means of a number of balls 18, 18 fitting half in each ofcircumferential grooves 19, 20 in the clutch member 16 and shaft 12,respectively, as shown in Fig. 3. A screw lug 21 normally closes thehole in the clutch member'16 through which the balls 18 are insertedinto the grooves in assembling the arts.

p A third clutch member 22, is splined or slidably mounted (withinlimits) on the shaft 12 beyond the clutch member 16. This slidableconnection is made through the provision of three sets of ball keys 23,23 located half in each of longitudinal grooves 24, 25 in the shaft12-.and clutch member 22, respectively. .Each set of keys preferablycomprises a pair of balls 23, and the three sets of balls and theirgrooves are spaced apart circumferentially about the clutch member 22,as shown in Fig. 6.

'- The opposed faces of the clutch members 16 and 22 have co-operatingjaws or clutch teeth 26, 27, respectively. The teeth 26 are arranged tofit within the spaces between the teeth 27 and have their engaging sidefaces inclined so that they may slip to disengage the clutch members 16and 22, when one member is turned with respect to the other in a mannerto be presently described.

'A relatively heavy coiled spring 28 surrounds the shaft 12 beyond theclutch member 22. This spring has its inner end against a washer 29 atthe outer end of the clutch member 22, and has its outer and bearingagainst a nut 30 screwed on the threaded portion 31 of the shaft 12. Bthis construction, the nut may be adjuste along the shaft 12 to regulatethe tension of the sprlng 28 and thus set the torque at which the teeth26, 27 of the clutch members 16, 22 will disengage on the setting of ascrew or nut. A set screw 32 carried by the nut is used to set the nutin its position of adjustment along the shaft. The washer 29 serves toclose the outer ends of the grooves 25 so that the balls 23 can not workor drop out of the same. The inner ends of these grooves are closed bythe clutch member '16, as shown in Fig. 3.

mally held disengaged or apart by a coiled spring 33 fitted in a hollowat the upper or innenend of the shaft 12. The inner end of this springcarries a plug 34 which is forced by the spring against the inner end ofthe hollow in the spindle 4. The spring 33 urges the shaft 12 outwardfrom the spindle 4 and thus normally maintains the clutch members 1.3,16 disengaged or apart, while the spring 28 normally holds the clutchmember 22 engaged with the one 16, except when said latter clutchmembers are held apart by the automatic release of my invention, to benow described.

The clutch members 16, 22 are provided on their opposed surfaces withmeans which, the moment the screw or nut becomes set or tight-- ened tothe proper tension,-will act to automatically move the clutch member 22outward against its spring 28 a distance sufficient to completelydisengage and separate the teeth 26, 27 of said members and positivelyhold the clutch members apart for substantially a complete revolution ofthe spindle 4 and immediately repeat the operation so that noopportunity is afforded for said teeth to slip or ratchet over eachother to wear or break on releasing the shaft 12 from the spindle 4. Themeans referred to may take the form of coacting arcuate slots andprojections on the respective clutch members arranged withian tlae (lineof their teeth, as shown in Figs.

The clutch 1nembersl3 and 16 are nor- As there shown. the teeth 26, 27of the clutch members 16 and 22 do not extend clear across their opposedfaces but are confined to their outer peripheries. This leaves the op edsurfaces of the members inside of the teeth flat except for the groovesand projections to be now described. The clutch member '16 is providedin this flat surface with two arcuate grooves 35, 36. These grooves arediametrically or oppositely disposed and are milled in the member 16with the groove 35 just inside the row of teeth 27 and with the groove36 at or close to the center hole or bore in the member through whichthe shaft 12 extends. Both grooves are cut on the same degree, and theinner groove 36, which is nearer the center, is shorter than the outergroove 35. The grooves 35, 36 are concentrically arranged with respectto the axial center of the member 16. but, being out of circumferentialalignment, provide different trackways 37, 38 on the face of the member16 for the arcuate projections 39, 40 on the other clutch member 22.

The projections 39, 40 are disposed on the face of the member 22 in th'esame relative positions as the grooves and, having the same shape as therooves and being slightly shorter, enter t e grooves when the clutchmembers 16, 22 go together for their teeth to 5 and 9, and thecorresponding ends of the engage, as shown in Fig. 3. The projections39, 40 project outward from the member 22 a distance slightly greaterthan the total lift required to clear the teeth of the clutch members,and the grooves 35, 36 are made deep enough to fully receive theprojections when said clutch members are engaged. The projections 39, 40should necessarily be a little shorter than the grooves in order not tointerfere when the clutch members 16, 22 snap together when the groovesand projections register.

At least one end of each groove 35, 36 is slightly beveled or inclined,as at 41 in Figs.

projections are also similarly inclined, as at 42 in Figs. 6 and 9. Thisis provided so that when the projections 39, 40 are forced against theends of the grooves, as when the clutch member 16 is turned by thespindle 4 with respect to the clutch member 22, the inclines 41, 42 willcause the. projections to ride outof the grooves, onto the trackways 37,38 and move the clutch member 22 from the one 16 for completelyseparatingjhe teeth of said members. As the'grooves 35, 36 are in thedifferent trackways 37, 38,'the clutch members 16, 22 are held apart forapproximately one full revolution of the clutch member 16, because theprojections 39, can not enter their grooves until after they havetraveled around their respective tracks for one revolution. When thisoccurs,the projections enter the grooves and the teeth 26, 27 engage. Ifthe tool is still pressed against the work, the projections willimmediately ride out of the grooves and the teeth will again beseparated and be held apart for another revolution and the actionrepeated until the tool is with- I drawn. By this action the teeth 26,27 would only momentarily engage once in each revolution, and thus cannot ratchet or slide over each other to wear or break, as heretofore.

A sleeve 43 is attached to the outer end of the extension 3 and projectsbeyond the same and forms a protecting housing or guard about all'of theclutches of the device. The lower end of the sleeve is turned inward toprojections 39, 40

provide a circular flange 44, which projects A socket 45 is shownsecured to the outer end of the shaft-12 to fit over a nut, as 46, to beset or tightened by the tool. For driving screws, asuitable holder for ascrew driving bit will be applied to the shaft 12 in place of the socket45. Sockets 45 of different sizes will be used for the different sizesand shapes of nuts to be operated on, and the same is true with respectto the driving bits for the different sizes of screws.

In operation, the operator grasps and holds the tool by its handles,turning on the current to the motor of the tool through a suitableswitch to set the tool in operation, and then .applies the socket 45over the nut 46 to be socket 45, and clutch members 16 and 22 are notrotated by the rotating spindle 4 at this time. The operator now forcesor presses the tool against the work, thereby closing up the clutchmembers 13, '16 and connecting the shaft 12 to the rapidly rotatingspindle 4, the quickly entering the grooves 35, 36 (if not alreadythere) so that the teeth of all of the clutches will be engaged to turnthe shaft by the spindle. In pressing the tool against the work, theflanged end 44 of the guard or sleeve 43 is moved forward out of contactwith the clutch member 22' (Fig. 4), so that the latter may yieldagainst,

its spring 28 when the projections 39, 40 ride out of the grooves toseparate the teeth of the clutch members 16," 22. This takes place themoment the nut becomes set to the proper tension. The tightened nutresists further turning of the shaft 12 and the clutch member 22, and asa result the clutch member 16 continues to rotate with the spindle 4.The teeth 26 of the member 16 begin to slide over those (27) of themember 22 and force the latter outward against the spring 28. Up tothispoint the automatic release has been inactive, as the projections39,40 are still in the 36 have been moved into contact with the beveledends 42 of the projections 39, 40 and the member 22 is forced fartheroutward from the member 16 to lift the teeth comthe spindle minus theplay between the width of the teeth. When the spindle about comn." no

and

pletes this revolution and the teeth pass over each other the last timeand before the teeth on member 16 have quite reached the space betweenthe teeth on member 22, the projections 39, drop into the grooves 35, 36and the teeth of the members will come together.

There is a little space or clearance between left square and a positivehold is provided between the projections and grooves for unscrewingscrews and nuts by the tool when the rotation of the spindle isreversed, as may be done with reversible tools. When the device is madeto set both right and left-handed screws and nuts, both ends of thegrooves and projections will be beveled.

The projections 39, 40 may be made integral with the clutch member 22,or they may be made independent of said member and afterward securedthereto as shown in Figs. 6 and 8. As there illustrated, an annularrecess 47 is turned-in the face of the member 22 between its teeth andits bore. On a ring 48 which is set in this recess are made the projections 39, 40. The ring is secured in the recess in any suitablemanner, rivets 49, 49 being shown for the purpose in Fig. 8.

With the teeth 26, 27 of the clutch members 16 and 22 completelyseparated and held apart when said clutch members are disengaged, thedrive through these clutch members will be interrupted, and no torquestrains will be transmitted through the clutch device by reason of therotation of the clutch member 16 with the clutch member 13, should thelast two clutch members be engaged at that time. The bevels or inclinesfor the teeth of the members of the clutch device and for the form theinnermost, intermediate and outermost members respectively of the clutchassembly. The intermediate member 16 cooperates with the innermost andthe outermost members 13 and 22 and forms-therewith main supplementalclutches, respectively. The main clutch is the driving clutch while thesupplemental clutch automatically releases the shaft from the positivedrive of the spindle on the development of a predetermined torsionalstress between the members of the supplemental'clutch through the tightening of the screw or nut without requiring a release of the mainclutch. This allows the continued rotation of the main clutch to effectan automatic re-engagement of the teeth of the supplemental -clutch assoon as the members thereof reach their single position of rotativeengagement. This automatically sets the clutch assembly for a drivingoperation without being required to stop the rotation to engage theclutch members.

The details of structure and arrangement of parts shown and describedmay be various- 1 changed and modified without departing rom the spiritand scope of my invention.

I claim as my invention:

1. In a clutch, a pair of axially alined clutch members havinginterengageable clutch teeth on their opposed faces, said members havingopposed grooves and projections adapted, when the projections are in thegrooves, to permit the teeth of the clutch. members to engage, and, whenthe projections ride out of the grooves, to separate said teeth,

said grooves and projections being arranged in two concentric tracks ofdifferent radii and each track preferably-having but one groove orprojection therein.

2. In a clutch, a pair of axially alined clutch -members havinginterengageable "clutch teeth on their opposed'faces with the teetharranged in ring form about the axis of the members and spaced radiallyoutward therefrom, and co-acting means on the opposed faces of themembers in'olfset relation to said ring of teeth to permitinterengagement of all of the teeth in a'single rotative position onlyof said members and operable upon the development of a predeterminedtorsional stress between them to automatically separate :said membersand hold their teeth out of positive driving engagement forsubstantiallyv a full rotation of one inember with respect to the other.

3. As an article of manufacture, a clutch" member having a circular bodyportion provided with a ring ofclutch teeth about the outer peripherythereof, and oppositely disposed arcuate projections on the clutch memqber within the ring of teeth, said projections extending outward fromthe clutch member to a greater extent than the teeth.

4. As an article of manufacture, a clutch member having a circular bodyportion provided with a ring of teeth about its outer periphery,oppositely disposed arcuate projections on said clutch member withinsaid ring of teeth, said projections extending outward from the clutchmember to a greater extent than the teeth with one projectioncircumferentially shorter than the other and nearer the center of thebody portion than the other projection.

5. As an article of manufacture, a clutch memes member having a circularbody portion with a ring of clutch teeth about its outer periphery, andarcuate grooves formed in the clutch member within said ring of teeth,said ooves being oppositely disposed and of difierent circumferentiallength and arranged one nearer the center of the body portion than theother. 7 6. In a clutch, separable clutch members 10 having a pluralityof teeth all of which interengage when driving one member by the other,said members being constructed to permit interengagement of all of theteeth thereof in a single rotative position only of the 16 members andoperable upon the development of a predetermined torsional stressbetween them to automatically separate the members and maintain theirteeth out of positive driving engagement for substantially a full revo-20 lution of one member with respect to the other, and means actingthrough the continued rotation of the rotating member for effecting theautomatic reengagement of all of the teeth of said members as soon asthe latter reaches said single position of rotative engagement.

7 In a clutch, separable clutch members having a plurality of teeth allof which interengage when driving one member by the other, said membersbeing constructed to permit interengagement of all of the teeth thereofin a single rotative position only of said members and operable upon thedevelopment of a predetermined torsional stress between them toautomatically separate the members and maintain their teeth out ofpositive driving engagement for substantially a full revolution of onemember with respect to the other, and means acting through the continuedrotation ofthe rotatingmemberfor effecting the automatic reengagement ofall of the teeth of said members as soon as the latter reaches saidsingle position of rotative engagement, said means being adjustable fordetermining said torsional stress.

In testimony whereof I afiix my signature.

AXEL LEVEDAHL.

